Updated Classification of Epileptic Seizures: Position paper of the International League Against Epilepsy

The ILAE Executive Committee has appointed a working group to evaluate the real-world application of the 2017 seizure classification and to recommend updates. The draft of this ILAE position paper is now open for public comments.

Please review all files before submitting your comments. Translations into 10 languages are available, and comments on these translations are also welcome. We encourage national chapters to propose translations into additional languages as well.

Draft: Updated Classification of Epileptic Seizures: Position paper of the International League Against Epilepsy

Translations: Arabic | Chinese | French | German | Italian | Japanese | Portuguese | Russian | Spanish | Ukrainian

Supplementary Material: PRISMA flow diagram for new systematic reviews | Literature search and evaluation | Definitions of generalized epileptic seizure types

Deadline: 16 October 2024

Comments

20 September 2024

The panel is congratulated with the proposed simplification, in particular by avoiding confusion about awareness and consciousness (and its translation).

Why not allow or even encourage TONIC-CLONIC-SEIZURE as an identical item in all the three boxes of Figure 2?

The seizure classification for the most common presentations should be used by patients, their relatives and caregivers, general neurologists, paediatricians, emergency physicians, stroke unit nurses, ..., and even by epileptologists. A presentation with a "tonic-clonic seizure from sleep with Todd's paresis " is common. "Focal to bilateral" is often assumed rather than observed. Certainly [1], people differ in their attitude to unanswerable questions [2]. If one forces observers to tick a box, a shockingly high percentage will report inobservable signs [3], and this may result in overdiagnosis. Further, allowing (and encouraging) tonic-clonic seizure as a sufficient descriptor may refer focal/generalized to the syndrome level. This should avoid quite some misuse of "generalized" (not only by generalists).

The relation of a seizure to sleep or time of day narrows the differential in TLOC quite a bit, helps with syndrome diagnosis, carries prognostic information that is going to have implications for driving [4] and will become relevant upon incorporation of Alzheimer's disease [5,6] into the classification of epilepsies. Where to put this information?

[1] Burton RA (2009). On being certain: Believing you are right even when you're not. Macmillan.
[2] Dubner SJ, Levitt S (2014) The Three Hardest Words in the English Language. Why learning to say "I don't know" is one of the best things you can do. Episode 167. freakonomics.com/podcast/the-three-hardest-words-in-the-english-language/
[3] Thijs RD, Wagenaar WA, Middelkoop HA, Wieling W, van Dijk JG (2008). Transient loss of consciousness through the eyes of a witness. Neurology, 71(21), 1713-1718.
[4] Lawn ND, Pang EW, Lee J., Dunne JW (2023). First seizure from sleep: clinical features and prognosis. Epilepsia, 64(10), 2714-2724.
[5] Larner AJ & Marson AG (2011). Epileptic seizures in Alzheimer's disease: another fine MESS? Journal of Alzheimer's Disease, 25(3), 417-419.
[6] Baker JFW (2019). A Study of Interactions Between Memory Disorders and Epilepsy: Epileptic Seizures in Dementia, Contrasted with Transient Epileptic Amnesia. Thesis. University of Exeter or Baker J et al. (2019). Seizure, 71, 83-92.

Bert Kleine (Germany)

18 September 2024

The classification has not been well accepted by neurologists because the previous focal simple and complex were better understood.

Rodrigo Riquelme (Chile)

18 September 2024

We propose to retain the terms focal onset and generalized onset as they help to decide about the choice of anti-seizure medications. While sodium channel blockers work well against focal onset epilepsy, we know that drugs working through GABAergic system like valproate work well against generalized onset epilepsy.

We propose to change the term "focal to bilateral tonic-clonic seizures" to "focal-to-bilateral motor seizures" as all may not have 'tonic-clonic' seizures. It is confusing that "spasms" have been categorized differently in generalized and focal seizures. We would appreciate more clarity regarding this.

In Section 1 "elementary motor phenomena" there are two terms which mean the same: "eye deviation" and "versive."

Mahesh Kamate (India)

18 September 2024

First and foremost, thank you for the tremendous effort and dedication you’ve put into updating the seizure classification system. This work is clearly the result of significant reflection and collaboration, and it represents an important step forward in making the classification more adaptable and accessible across clinical settings globally. While the updates are much appreciated, I would like to offer a few suggestions that might further enhance the classification’s practicality and usability:

  1. Given how widely this classification will be used, it might be worth considering the involvement of a graphic designer to refine the figures, particularly Figures 1 and 2. A clearer, more engaging layout would not only improve the readability of these visuals but also enhance their effectiveness in educational and clinical settings.
  2. The simplification of terms, such as replacing “Focal Preserved Consciousness Seizure” with "Focal Conscious Seizure" or "Focal Unconscious Seizure," could make the classification easier to use in practice. This streamlined language would help reduce confusion for both clinicians and patients, making the classification more accessible.
  3. Although the addition of negative myoclonus is a welcome change, ensuring clear differentiation between negative and positive myoclonus, especially in the context of PME and GGE, would greatly improve diagnostic accuracy. Adding rare seizure types, such as clonic-tonic-clonic and tonic-atonic seizures, would provide further clarity and utility in both research and clinical practice.
  4. Many patients experience seizures without witnesses, and a category for "unobserved" seizures would help capture these events. Including such a category would provide a more complete diagnostic framework and allow for more accurate seizure tracking in clinical care.
  5. Reflex seizures, particularly those triggered by specific stimuli, have been well-documented and are significant in certain populations. Incorporating reflex seizures into the classification would make it more comprehensive and provide a better tool for managing patients with photosensitive or other reflex epilepsy types.
  6. Some of the terms used in the translated versions, like "consapevolezza integra" in the Italian version, could benefit from minor adjustments. Terms such as "coscienza intatta" or "coscienza preservata" would likely be clearer and more consistent with clinical terminology, making the classification more user-friendly for non-English-speaking clinicians.

Pasquale Striano (Italy)

16 September 2024

The basic version graphic seems to divide generalised seizures into "absence seizures" or "motor seizures". Given absences often have motor components I wonder whether this is an unhelpful simplification as will imply to the reader absences with motor elements cannot be absences. An example of an alternative simplified group here might be absence seizures, tonic-clonic seizures, or other generalized seizures.

Colin Dunkley

13 September 2024

I would like to express my gratitude to the new ILAE Task Force for the opportunity to discuss the proposed revision of the seizure classification system.

In my view, the previous classification's exclusive focus on "awareness" was a significant weakness. It has been counterintuitive to classify a responsive individual as "unaware" simply because memory encoding or consolidation during the ictal period is impaired. Therefore, I appreciate the return to earlier classifications that consider both awareness and responsiveness as operational criteria for consciousness.

I also acknowledge that using the first semiological manifestation of a seizure as a classifier, as used in the last classification, has both advantages and disadvantages. The initial observed element may not fully represent the global phenomenology of focal seizures, which can vary greatly depending on the propagation pathways and the gradual involvement of multiple symptomatogenic areas by ictal activity.

However, there are aspects of the new classification that I believe warrant further discussion and reconsideration:

  1. Levels of classification: The term “aphasic” is proposed to be used at the same level as “autonomic.” I strongly recommend retaining previous terms such as “cognitive” or “affective” at this classification level, as aphasia is just one possible manifestation of cognitive ictal impairment, similar to sweating being one manifestation of an autonomic phenomenon.
  2. Definition “observable”: The term "observable" requires a clear definition and possibly revision (e.g. by “objective”). It appears to describe objectively verifiable aspects of a seizure, as opposed to elements accessible only through subjective introspection. What is considered "observable" varies depending on the degree of scrutiny applied during observation. This issue is not limited to cognitive phenomena, which may or may not be observed depending on patient interaction with their environment, but also extends to autonomic signs. For instance, when should a documented heart rate be classified as ictal tachycardia? Definitions of ictal tachycardia vary widely across research studies. Is ictal sweating considered observable only when it becomes visible, or if it is just detected through electrodermal activity (EDA) measurements? How observable is hypersalivation?

Is "urinary urge" really an observable or subjective phenomenon?

The term “observable” can imply that a semiological sign has been directly observed (e.g., through inspection) or that it could be observed given the application of specific methodologies. If “observable” implies the potential for observation, this would lead to speculative classifications. Conversely, if actual observation is required, could the use of new techniques, such as wearable devices, shift a seizure classification from “not observable” to “observable”? Such methodological advancements may obscure the accurate assessment of epilepsy progression or outcomes if applied, for example, to outcome evaluations based on the resulting classification.

Finally, a classification system aims to standardize terminology for clinical communication and research phenotyping. For these objectives to be met, consistency and stability over time are crucial. Therefore, I value the comprehensive expertise of ILAE members in developing a classification system with lasting and widespread adoption in epileptology and neurology. Given that the previous classification was introduced only seven years ago, frequent reclassifications and terminological changes might disrupt the field and hinder the acceptance of the system among non-specialist neurologists.

With best regards,

Andreas Schulze-Bonhage (Germany)

11 September 2024

I am sending my comments on this update of the type of epileptic seizures: observations on the translation into Spanish and consciousness in focal epilepsy.

Observations on the translation into Spanish

  1. Escriben conciencia (con c) y consciencia (sc) en el mismo documento
    Considero que debe ser escrito en español con sc ya que consciencia tiene un sentido mas amplio de la incapacidad del paciente para responder y no tener consciencia, que es el planteamiento del término. Conciencia con c es mas de uso para un término moral (eso quedará en tu conciencia).
  2. En el apartado de crisis de ausencia se escribe crisis con mioclonía palpebral son o sin alteración de consciencia. Lo cual es un error, en este apartado se trata de las mioclonías palpebrales con o sin ausencia (como lo había descrito originalmente Peter Jeavons), es un error que debe corregirse.
  3. En el último aparatado de la clasificación, considero debe cambiarse el termino en español de No clasificable por el de No clasificada. Un concepto es que no sea posible clasificar una crisis epiléptica, pero la mayoría de las veces es no clasificada porque no tenemos en el momento de clasificar, claridad de la semiología de la crisis del paciente.

Consciousness in focal epilepsy

Probably the most debated point in the classification of the type of seizure is the level of consciousness in focal seizures. It is difficult to find a single word that allows establishing the idea of what this means, especially when applying it in different languages. Therefore, it is only necessary to clarify what consciousness means for epilepsy, to establish the concept.

Proposal: Consciousness in epilepsy is understood as when a patient maintains three characteristics during his seizure: responsiveness, full memory of the event, and knowledge of self and environment.

One of them is not enough, all three must be present, if one of them is not present, then the patient will have altered consciousness. It must be established that knowing the consciousness during a focal seizure requires an active and dynamic evaluation during the seizure by a witness.

Muchas Gracias
Thank you

Juan Carlos Reséndiz Aparicio (Mexico)

7 September 2024

Dear Prof Cross, dear Prof Beniczky, dear Prof Trinka, dear members of the task force,
I want to congratulate you to your masterpiece of work. I would like to share a few thoughts with you:

  1. The authors correctly introduced the category “unknown” with the proposed classifiers, i.e., (1) focal and general, and (2) preserved or impaired consciousness. However, the classifier (3) with or without observable manifestations does not have this important category “unknown”.
    • Could it be useful to extend the grammar of this taxonomy and provide the category of “unknown” to all three major classifiers in focal seizures?
  2. In close relation to this, the authors proposed
    1.1-1 with observable manifestations (CLASSIFIER)
    1.1.-2 without observable manifestations (CLASSIFER)
    1.1.-3 serial description (DESCRIPTOR)
    • I would like to suggest that CLASSIFIERS and DESCRIPTORS are not mixed in the taxonomical hierarchy. It should become clear from the taxonomic code what kind of information is provided or required. Could the following approach be helpful, please?
      1.1 with observable manifestations (CLASSIFIER)
      1.1.-D DESCRIPTOR of 1.1
      1.2 without observable manifestations (CLASSIFER)
      1.3 unknown (CLASSIFIER)
      Alternatively: I (Roman 1) serial description (DESCRIPTOR), i.e. Roman numbers (I, II, III, ) for DESCRIPTORS.
  3. The somatotopic modifiers under point 4 Cognitive & language phenomenon include aphasia.
    • Could it be useful to distinguish between “receptive aphasia”, “expressive aphasia”, “global aphasia”, “other”?
    • Could it be useful to include specific neuropsychological signs or syndromes (e.g. frontal disinhibition, Klüver-Bucy, severe agitation)?
    • Could it be useful to add “slowed thinking”?
    • Could it be useful to include “out of body experience”?
    • Could it be useful to include “feeling as if watching myself from behind/above”?
  4. Should a somatotopic modifier of “behavior” be introduced or added to the cognitive group?
    • Could it be helpful to distinguish between “behavior: dangerous in activities of daily living”, e.g. putting boots into the oven during ictal confusion?
    • Could it be helpful to state that the patients suffers from postictal depression or postictal aggressive behavior? – It seems to be warranted to include the postictal phase to the seizure classification as this has impact on patient management.
  5. Could it be useful to include a category of “triggers”. – Triggers might help reduce seizure frequency simply by preventing the exposure to the trigger.
    Sleep deprivation, exposure to flicker light, hyperventilation,
    Listening to certain music, reading, other.
    (This could be implemented like this:
    1.1 with observable manifestations
    1.1.-D semiology description in chronological sequ.
    1.1.-T relevant triggers )
  6. The authors successfully applied the concept of consciousness with subdomains of awareness and responsiveness. However, in daily work for people with epilepsy it is highly relevant if the patient can recall the seizures as such. There are several situations in which the patient has a full memory for the time during the seizure and was always adequately responsive but herself/himself cannot recall that a seizure has taken place, e.g. with behavioral observable manifestation. Relatives frequently report “my son did not realize that there was a seizure. He remembers everything. At school they also report adequate responses, also at home, but I as his mother always detect them”.
    This new proposal bears the chance to address all components of consciousness. Could it be helpful to characterize consciousness in the domains awareness, responsiveness, and recall of the events as such? (This could impact on design of studies.)
  7. The classification aims to “establish a common language for all healthcare professionals (HCP) involved in epilepsy care”.
    Could it be helpful to think this highly important point in new ways? What kind of communication could prove useful between Epileptologist in epilepsy center with stereo-EEG (SEEG), Epileptologist in epileptsy center with presurgical evaluation but without SEEG, Epileptologist in a hospital without presurgical evaluation, Epileptologist in personal praxis, Epilepsy nurses dedicated to taking care of patients with epilepsy, General neurologist in hospital, General neurologist in personal praxis, Occupational physician deciding on whether a job is suitable or not. General practitioner, family doctor.
    Physiotherapists, ergotherapists, logopedics, neuropsychologists, who train the patient according to the diagnoses established by physicians. Nurses on other departments than neurology in hospital.
    The list is still not complete, but a few of the above listed HCPs might have difficulties with optimizing their therapeutic approach when reading “FPC 1.1 with observable manifestations: epigastric aura->oroalimentary automatisms + gestural automatisms with the right hand + preserved awareness and responsiveness” (example provided by authors). In order to establish a communication system that provides all HCP with fast and relevant information there could be new approaches: Could it be helpful to communicate “Focal seizure with preserved consciousness: always aware, always responsive, recalls the occurance of a seizure as such, no dangerous behavior”? [(A1-R1-M1-B1)] The more HCPs understand our language and the more epileptologists transfer their findings into ADLs the more adequate medical support and social integration will be given to people with epilepsy.

Thank you for reading.
Kind regards,

Markus Leitinger (Austria)

6 September 2024

When I was a neurology resident, I learned the term "crise parcial simples" and "crise parcial complexa". For me, it's short, simple and practical to use. The term "impaired consciousness" (in Portuguese - comprometimento de consciência) is long and tricky, because consciousness is partially preserved, and it's easier to speak "complex" because it's really complex to talk about consciousness, awareness and responsiveness! I agree that focal is better than partial, so I would rather say "complex focal seizure" (in Portuguese - crise focal complexa (CFC)), and "simple focal seizure" (in Portuguese - crise focal simples (CFS)). The acronym in Portuguese is easier - CFC, CFS.

Camila Hobi (Brazil)

6 September 2024

Congratulations to the work team. It is clear and updated without ambiguity.

Angela Gnanadurai

5 September 2024

Can we include spasms/ tonic seizures in focal seizure clarification just to emphasise that these seizure types are not always generalised in nature.

Sandeep Patil (India)

5 September 2024

The revised classification is comprehensive and easier to translate to the local language. I have a challenge with negative myoclonus, the identification of. I work in a resource constraint environment, where EEG assessments are not routinely available and so will tend to use clinical evaluation.

Well done to the committee.

Gwendoline Kandawasvika (Zimbabwe)

4 September 2024

Attempting to classify seizures better is a valiant effort and is to be applauded. Kudos to the team for putting in the effort.

However, I would advocate strongly for keeping the same names as before. Changing names every few years leads to an incredibly fragmented literature and difficulty in communicating with non-epilepsy specialists who do not understand why we keep changing things (neither do I). We have community physicians who speak of petit mal, complex partial seizures, and university-based physicians who speak of dyscognitive seizures, and focal impaired awareness seizures depending on when each person trained. This terminology heterogeneity affects research in trying to put together different terminologies over the years. This also detracts new trainees who find the field very confusing and move on to other areas.

FAS -> FPC and FIAS -> FIC may seem like progress, but is a backwards step in my opinion. I am sure the team had similar discussions between this and reached this consensus, similar to all the other times in the past when the names were changed, and similar to the future times when this will change. If the price to pay for progress is added confusion, perhaps progress is not worth the price. Hope this highly qualified team does not take this as unwarranted criticism, and adds this opinion to the mix.

Zulfi Haneef

2 September 2024

Firstly, congratulations in achieving a feat and making such a detailed classification with newer data. I have two comments.

  1. In the case of only autonomic semiology, where do they need to be placed?
  2. Negative myoclonic seizure need to be more clarified in terms of etiology for its varied presentations.

Thank you,

Gautam Gangopadhyay (India)

29 August 2024

I congratulate the working group on this updated classification. This classification will appear on thousands of PowerPoint slides. May I humbly suggest consulting a graphic designer for the final print version of the manuscript to enhance the style and legibility of Figures 1 and 2.

Marian Galovic (Switzerland)

28 August 2024

In the CDKL5 Deficiency Disorder (CDD), there is a very characteristic seizure type characterized by the hypermotor-tonic-spasms sequence.

It was first described in 2011, see Klein KM Yendle SC Harvey AS Antony JH Wallace G Bienvenu T Scheffer IE. A distinctive seizure type in patients with CDKL5 mutations: Hypermotor-tonic-spasms sequence. Neurology. 2011

More than half of CDD patients present either hypermotor-tonic-spasm seizures or tonic-spasm seizures (ref: Demarest ST, Olson HE, et al 2019. CDKL5 deficiency disorder: Relationship between genotype, epilepsy, cortical visual impairment, and development. Epilepsia)

These characteristic seizures in CDD patients pose challenges for seizure counting and classification in trials.

This is a request to please provide guidance in the ILAE seizure classification for how to classify these seizures: e.g. a subtype of tonic seizures, a subtype of epileptic spams, a separate type of seizure.

One good example for how to classify some sequence seizures is the classification of “2.2.2.3. Absence-to-tonic-clonic seizure” as a subtype of GTC seizures in Table 1. A possibility would be to similarly include the tonic-to-spasm seizure so often seen in CDD patients under "2.2.1. Generalized motor seizures – other than tonic-clonic”.

But wherever you place it, my request is to please consider the inclusion of the tonic-to-spasm seizure because it is so common in CDD patients and it will make our clinical trials easier if it would have a direct map into the updated ILAE seizure classification.

Thank you so much.

Ana Mingorance (UK)

28 August 2024

Thank you to the working group for the proposed changes, most of which I believe represent improvements. In addition, the authors have to be commended for providing simultaneous translations, which I think is of major importance for promoting wide implementation.

I have two comments:

  1. I suggest to replace "Focal Preserved Consciousness Seizure" and "Focal Impaired Consciousness Seizure" with "Focal Conscious Seizure" and "Focal Unconscious Seizure". Although I acknowledge that the latter may not be entirely correct in all cases, I would favour simplicity.
  2. The term "Generalized Negative Myoclonic Seizure" deserves some further explanation/description.

Chantal Depondt

26 August 2024

Excellent update. I appreciate the addition of myoclonic-tonic-clonic and absence-tonic-clonic along the lines of focal-tonic-clonic. There should be a category of clonic-tonic-clonic, albeit rare, but should be a part of the new expansion.

Charles Akos Szabo (US)

26 August 2024

I suggest to create a new topic with genetic epileptic syndromes like Dravet, and Alice in Wonderland. I also suggest to differentiate epilepsy crises due to their origin in the brain with their more common phenotypes as like as frontal lobe epilepsies and parietal epilepsies.

Antonio Carlos Borges (Brazil)

23 August 2024

As Chair of the 2017 Seizure Classification taskforce, I am gratified that the Updated Classification revisions are limited and based on literature, seven years of experience in the field and expert consensus. The structure and majority of terminology from the 2017 classification is retained. The revision supports the decision to classify by the first manifestation, rather than the most prominent, because the first identifies the part of brain or network pointing to the most likely site of an important lesion. The revision also continues to allow use — when available — of ancillary information and not exclusively on semiology. 

One of the changes is introduction of the term “consciousness” in place of “awareness.” Alteration of consciousness always has been a key classifier of seizures, but the term has not before been in the name of the seizure type (for example, “temporal lobe seizure,” “psychomotor seizure,” “complex partial seizure”). The 2017 Task Force thought that a typical seizure with automatisms or freezing of activity would not be perceived by the public as loss or alteration of consciousness. In the popular view, loss of consciousness conveys someone lying on the floor “out cold.” We looked for surrogates. Possibilities were awareness, responsiveness, memory, any or all of which can occur during a seizure. Responsiveness is of great operational importance because its loss is what crashes the car. However, responsiveness usually cannot be assayed retrospectively, unless someone was present to test it at the time of a seizure. Therefore, we chose awareness during the event as a surrogate. We also made note that many languages did not make a clear distinction between “awareness” and “consciousness.”

A seizure with no observable manifestations probably is sensory, emotional or autonomic. We thought it was worth specifying which of these was present at the start of the seizure, but apparently the updated version does not, and lumps them all under “without observable manifestations.”

Focal and unknown categories now mention sequential semiological classifications. Of course, these should be in the documentation of seizures, but they are not seizure CLASSIFICATIONS. It would be impossible to list all sequential symptoms and signs and all propagation patterns during seizures. The 2017 Task Force chose to list only the most important one, which is focal to bilateral tonic-clonic. That seizure type is maintained.

A new seizure type of negative myoclonic seizures has been added, and I have no quarrel with that. Over the past years, I have received several e-mails nominating other seizure types, including tonic-atonic, atonic-tonic, absence to tonic-clonic. At some point, a classification becomes unwieldy, so inclusionary decisions had to be made.

I have a few of my own criticisms of the 2017 seizure classification. The main one is that it is not based on fundamental science and does not explain why the brain generates a discrete number of different seizure types. Our state of knowledge did not permit a scientific classification. It does not encompass the large variety of propagation patterns. The categorization as “unknown” is a feature of our ignorance, not of the seizure. Some seizures could be classified more than one way in the 2017 scheme, for example sensory versus autonomic or hallucinations as cognitive versus sensory. Many “favorite” seizure types were not included. For the most part, the revised classification does not solve these problems, but may bring terminology into simpler or more common usage. Hopefully, the energy to re-label and re-educate will be justified by greater accuracy and understanding.

Robert S. Fisher (US)

22 August 2024

In the section on "Cognitive & language phenomena," I recommend adding 2 categories: 1) Confusion, 2) Other focal cognitive deficits (eg, anosognosia, apraxia, neglect,). #1 is common and can occur in the absence of aphasia or amnesia. Further, patients can have amnesia without confusion. #2 is rare but these deficits have been reported in the literature. Since focal seizures may inhibit normal neural function, a variety of negative cognitive deficits that are topographically related to the site of cortical ictal activity. The present Somatotopic Modifiers do not account for the variety of potential ictal cognitive deficits.

It would have been nice to have a vowel in FPC to allow easy reference to focal preserved consciousness seizure and focal impaired consciousness seizures (FIC) without having to say the whole phrase when discussing with colleagues and trainees. Consider focal aware consciousness (FAC); note that this may help patients and their family understand that they can have a focal seizure where they appear conscious with eyes open and may even interact partly with the environment, but are not aware for FIC vs FAC seizures.

Thank you for your consideration.

Kimford Meador (US)

22 August 2024

Thank you for your appreciation, and it's a pleasure to assist with the revisions. I am an epileptologist from the southwest of Iran, a region with a significant prevalence of epilepsy and epilepsy syndromes among children. My experience has been deeply shaped by the numerous debates and discussions with mentors, colleagues, epilepsy fellows, adult neurology residents, and even interns and students regarding consciousness and awareness in affected children. Often, these discussions would become repetitive, prompting me to simplify the concept by suggesting they observe the child's response to stimuli. It is gratifying to see others echo my thoughts on this matter.

Moreover, I am particularly thankful for the recent definitive classification of absence seizures. Previously categorized merely as generalized non-motor seizures, this redefinition acknowledges their distinct characteristics, including symptoms like eye-blinking, which were often overlooked or underestimated. This clarification is a significant step forward and aligns with the clinical realities I face, where absence seizures present unique diagnostic and management challenges.

This updated approach not only reflects a better understanding of the condition but also promises to alleviate many of the ongoing debates among neurologists and epileptologists. By establishing clearer definitions, we can improve both daily practice and research, leading to more targeted interventions and better outcomes for our young patients. The recognition of specific seizure phenomena, like eye-blinking during absence seizures, enhances our diagnostic accuracy and enriches our understanding, ultimately benefiting the comprehensive care we strive to provide. Such advancements in our field are crucial. They not only refine our medical practices but also foster a more nuanced understanding among all healthcare providers involved in the care of children with epilepsy. This collective progress is essential for advancing our field and improving the lives of those affected by these challenging conditions. As we continue to build on these foundations, I remain hopeful for the future of epilepsy treatment and research, particularly in regions like ours where the need is profound and the impact of such advancements can be truly life-changing.

Reza Azizimalamiri (Iran)

22 August 2024

Looks very clear and sensible; I think an improvement.

Hannah Cock (UK)

21 August 2024

Dear Prof Cross, dear Prof Beniczky, dear Prof Trinka, dear colleagues of the ILAE TASK FORCE on seizure classification,

I have read your precious proposal with great interest and wish to congratulate you to this outstanding achievement.

I would like to add a few thoughts which could give way for important options.

I am aware that the ideal approach to a classification is to combine a simplicity for a broad applicability on the one hand, and a granularity which captures the complexity of real life on the other hand.

In daily practice I often wished to have a classification at hand which allowed me to address the change of semiology over time during a seizure, the individual awareness during a seizure, the reactivity to external stimuli in a clinical meaning, the existence of potentially dangerous behaviour, the individual memorization of whether a seizure has occurred at all, and a quick and clear communication and documentation tool.

This would have been helpful as it might have implications on driving a car, taking care of small children, might interfere with workplace activities, might impact on seizure counting (predisposition to underreporting), impacts on design of interventional studies, epidemiology in general and relative frequency in an individual, and neurological topography to associate specific semiological patterns to certain brain areas as a prerequisite for epilepsy surgery.

The complexity I would like to address is

AWARENESS A:

  • A1->1 (A11) means that the patient is aware at the beginning (A1) and at the end (-1) of a seizure.
  • A1->0 (A10) means that the patient is aware at the beginning (A1) but not at the end (-0) of a seizure.
  • A0->0 (A00) means that the patient is not aware at the beginning (A0) nor at the end (-0) of a seizure.

RESPONSIVENESS R:

  • R1->1 (R11) means that the patient is responsive at the beginning (R1) and at the end (-1) of a seizure.
  • R1->0 (R10) means that the patient is responsive at the beginning (R1) but not at the end (-0) of a seizure.
  • R0->0 (R00) means that the patient is not responsive at the beginning (R0) nor at the end (-0) of a seizure.
  • Rx->x (Rxx) the patient does not know whether she/he is responsive, there are no witnesses so far.

BEHAVIOR as part of seizure semiology, BUT NOT DANGEROUS B:

  • B1->1 (B11) means that the patient shows no dangerous behavior (e.g. putting boots into the oven) at the beginning (R1) and at the end (-1) of a seizure.
  • B1->0 (B10) means that the patient shows no dangerous behavior (e.g. putting boots into the oven) at the beginning (R1) but does so at the end (-0) of a seizure.
  • B0->0 (B00) means that the patient shows dangerous behavior at the beginning (B0) and at the end (-0) of a seizure (i.e., throughout the seizure).

MEMORIZATION whether a seizure has occurred at all M:

  • M1 the patient remembers/”memorizes” that a seizure has occurred.
  • M1d the patient directly remembers/”memorizes” that a seizure has occurred, i.e., the patient recalls parts of semiology.
  • M1i the patient INdirectly remembers/”memorizes” that a seizure has occurred, i.e., the patient concludes from aspects other than semiology that a seizure must have occurred, e.g. blood and saliva on the pillow.
  • M1x the patient remembers the seizure as such but it is unknown by which mechanism.

Examples:

A11 R11 B11 M1d:

This is a seizure in which the patient is fully aware from the beginning throughout the whole seizure, (A1->1, A11), always responsive, (R1->1, R11), always with adequate behaviour, (B1->1, B11), memorizes directly that the she/he had a seizure and can report this (M1d).

A10 R11 B11 M1:

This is a seizure in which the patient is fully aware only at the beginning of the seizure, (A1->0, A10), always responsive, (R1->1, R11), always with adequate behaviour (B1->1, B11), memorizes that the she/he had a seizure and can report this (M1x). The physician does not know how the patient remebers that there was a seizure.

A10 R10 Bxx M0

This is a seizure in which the patient is fully aware only at the beginning of the seizure (A1->0, A10), responsive only at the beginning of the seizure (R1->0, R10), the behaviour is not reported/ no witnesses available (Bxx), does not memorize that the she/he had a seizure.

(M0) A10 R10 Bx0 M0

This is a seizure in which the patient is fully aware only at the beginning of the seizure (A1->0, A10), responsive only at the beginning of the seizure (R1->0, R10), the behaviour is not reported at the beginning, but later shows inadequate behaviour (e.g. puts boots into the oven) (Bx0), and does not memorize that the she/he had a seizure (M0).

Clinical examples:

  1. For a young mother it would be quite a success to improve from R11 Bx0 to R11 B11 as her child is no longer endangered by inadequate dangerous behaviour.
  2. A pharmaceutical company may wish to include only patients with Aany Rany Bany M1 to guarantee adequate seizure reporting and counting.
  3. There should be no problems at a suitable workplace for a patient who has seizures classified as A11 R11 B11 M1d.
  4. In presurgical evaluation, A10 R10 B11 M1 has a different meaning than A00 R00 B10 M0.

Possibilities for extension:

In presurgical evaluation it might be highly relevant if the patient speaks during the seizure, therefore:

  • S11 (S11) means that the patient speaks adequately throughout the seizure, an involvement of the speech relevant eloquent cortex does not occur.
  • S1->0 (S10) means that the patient speaks adequately at the beginning, but there is impairment of speech at the end of the seizure.
  • SX->X (SXX) Speech was not witnessed or tested during the seizure.
  • SX->X/1 (SXX/1) Speech was not witnessed or tested during the seizure. However, speech was normal in the postictal testing.

I do not yet know what “unknown” should exactly mean regarding consciousness:

  • We do not know whether the patient is aware during the seizure.
  • We do not know whether the patient is responsive during the seizure.
  • We do not know whether the patient memorizes her/his seizure.
  • Any combination of the above.

Thank you so much for reading until this point. – Please allow uploads of PDFs to provide figures.

Kind regards. 

Markus Leitinger (Austria)

17 August 2024

If we can add reflex tonic seizure to tonic seizure classification and also reflex myoclonic seizure.

Sawsan Albazi (Iraq)